In HDFS Federation, can i create the setup with one extra namenode as standby namenode for all namenodes?

Question

In HDFS Federation, I came to know that each namenode having one namespace require one namenode as standby namenode. That means if I have 10 namenodes, then I should have 10 standby namenodes.

Is it possible to have one extra namenode as the standby namenode for all the namenodes so that if one of the namenode goes down then the standby namenode would become the active namenode as in the case of the one extra harddisk used in RAID 5

Answer 1

No it is not possible to have so because each namenode in the HDFS federation would have the separate namespaces and each namespace requires separate and individual standby namespace/namenode. It is not possible to have one single namespace or namenode for all the namenodes present in the cluster.